Macrophages: Diversity of phenotypes and functions, interaction with foreign materials

Abstract

According to "M1/M2" paradigm two distinct subsets of macrophages have been proposed - classically (M1) or alternatively (M2) activated macrophages that express different receptors, cytokines, chemokines, growth factors and effector molecules but recent evidence suggests that in respond to changed environmental stimuli they can demonstrate unique properties which do not allow to attribute them neither to M1 nor to M2 population. Macrophages play a pivotal role in foreign body reaction following installation of catheters, stents prosthesis, dental implants. Macrophages englobe wear particles around joint prosthesis initiating an inflammation in periprosthetic tissues and osteolysis, control fibroproliferation and formation of the fibrous capsule surrounding foreign bodies. A brief overview of events leading to migration, adhesion and activation of macrophages, and analysis of their functional characteristics on different surfaces including biodegradable and non-biodegradable materials in vivo and in vitro are presented.